s is rarely
necessary; for if properly placed, there is generally room for all;
yet sometimes the expansion of the felt or warping of the shank makes
cutting necessary.

7. _Dampers_.--The dampers in the square action depend entirely upon
their weight for their efficiency in damping the strings and returning
after being raised by the key. Often, after the key is struck, the
damper will not return to its place and the string is undamped. This
is generally found to be caused by the wire sticking in the hole
through which it passes, the wire being rusty or bent or some foreign
substance being in the hole round the wire. The bushing cloth in the
hole may be in such condition as to retard the free passage of the
damper wire, in which case the wire may be heated with a match and run
up and down a few times through the hole, which will free it. The
damper may not fall readily on account of a sluggish joint in the
flange. Work it back and forth as far as it will go a few times; if
necessary, take it off the damper rail and look for the cause of the
trouble.

Damper flanges get loose on the damper rail and work to one side,
causing defective damping and rattling. See that they are all tight,
and in their places.

Damper lifter buttons sometimes hold the damper off the string. See
that the top button falls so low that the damper lever does not touch
it when the key is released. This is accomplished by altering the
lower button. Examine the damper felts to see if they are moth-eaten,
or have become hardened or in any way impaired. Notice the adjustment
of the shade; that it is not too low or too high. The purpose of the
shade is to prevent the damper levers from flying up; but it should be
high enough so that the levers do not touch it when the key is
depressed gently.

Defective damping is one of the most annoying conditions, and when one
is employed to regulate a piano thoroughly and put it in order, he
should see that no key is left in which this occurs. Strike each key
and immediately let it up to see if it stops the sound quickly, or, in
other words, damps perfectly; if it does not, find the cause and
regulate until satisfactory.

8. _The grand action_ being, in principle, practically the same as
that of the square and the upright, containing the same mechanism as
is found in those actions, it is needless to give special instructions
concerning it; as the previous work has given the pupil a thorough
knowledge of the r